Greater Austin/Travis Regional Radio System (GATRRS) Technical Details

System Technical Details

• 95% coverage for portable radio worn on hip inside a -10 dB building (residential or light commercial structure) throughout City of Austin and Travis County.
• 95% coverage for portable radio worn on hip inside a -20 dB building located within defined geographical area of Austin.
• All digital system to reduce monitoring of radio transmissions - Encryption provided to special Law Enforcement talk groups.

Note the mention of designing the system to reduce public monitoring of a public funded public safety system.

Below is a system map of simulcast sites and IR (Intelli-Repeater Sites) making up this system. This map portrays Travis County sites only and does not include Williamson County, the Middle Rio Grande Valley sites or any of the planned expansion counties.

This system is implemented as a two layer simulcast system with "intellirepeater" fill-in sites within Austin/Travis County and networked multisite nodes for other counties/areas.

Austin/TC EMS and TCSO function on the countywide layer comprised of 11 towers supporting 23 simultaneous conversations. The City wide layer, primarily east of 620, is comprised of 7 towers supporting 19 simultaneous conversations. Additionally, individual intellirepeater sites serve difficult coverage areas such as Barton Creek and Hamilton Pool. Williamson County joined the system in November 2007 migrating their frequencies and towers implemented as a networked site (site 120). The Middle Rio Grande Valley is also implemented as a networked site. Any unit/talkgroup can appear on any site in this system.

Simulcast 1 is mostly Public Safety: including APD, EMS, AFD, Travis County Sheriff, Corrections, Travis County Parks

Simulcast 2 is mostly city and county services including convention center, trash, water, streets, signal repair, Austin Energy, Animal Control, flood control, school crossing guards, Parks and Rec, AISD including busses, etc.

Several counties in Central Texas are planning to join this system forming a wide-area networked system. This includes Bastrop, Caldwell, Fayette and Lee counties. Combining these systems in this fashion will enable communications between any unit/agency from anywhere within the combined coverage area. As these individual counties migrate to P25 digital they will merge with Austin/Travis County system increasing the total coverage area for all users.

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